Due to prior processing, surfaces of solid materials, such as metal or glass, may have thereon a layer of residual carbon in various forms. Such surface carbon can interfere with subsequent treatment of the surface. For example, steel plate or sheet has residual organic compounds on the surfaces thereof which come from lubricants used in rolling the metal. The carbon is particularly difficult to remove after the steel has been annealed. When the steel is later treated, e.g., phosphatized or painted, the residual carbon on the surface of the steel can interfere with effective treatment, thereby increasing the potential for corrosion of the steel in subsequent applications. In the past, acid or alkaline washes have been used in an effort to clean the metal surface and remove residual carbon.